I have an Edelbrock 600 on a chevy 350. Has a mild cam in it and and overall the cars runs great. Running about 34 degrees total timing and the plugs look like they should, not rich and not to lean. I have a bog or a stumble then the secondarys come in when floor it from a standing start or when you pass someone. I changed the jets on the secondary to .101 and this did help, but I can't get rid of the hesitation. Any suggestions on a meter rod, jet combo. I called Edelbrock and they said put in silver springs, did not work. I called back and the tech guy he didn't really know what could be the problem. I guess I am to use to fuel injection. Any help would be appreciated. Thanks Robbie
Edelbrock Carb problem
- Thread starter trhccd
- Start date
donsrods
Member
I have exactly the same thing going on with the same carb, not sure what is up because I have two of them on my '27 with straight linkage and never had a bog there. My Son is running two of them on his 302 and no bog there either.
I changed the hole setting on the accelerator pump arm and it helped a little, but still not perfect. If I stomp it the thing dips for a second then comes on like gangbusters. Normally this would indicate the secondaries coming in too soon but on these you can't adjust that.
I haven't really played with it much and rarely punch it, so it isn't an issue, but I should take care of it just to make it right. Hope you and I get some input from others who may have solved it.
I changed the hole setting on the accelerator pump arm and it helped a little, but still not perfect. If I stomp it the thing dips for a second then comes on like gangbusters. Normally this would indicate the secondaries coming in too soon but on these you can't adjust that.
I haven't really played with it much and rarely punch it, so it isn't an issue, but I should take care of it just to make it right. Hope you and I get some input from others who may have solved it.
norseman
Member
Guessing its a timing issue too but you could also put a larger cc accelerator pump. Or you could have a semi plugged accelerator pump circuit. Possibly from sitting the check ball might have got varnished into place. I know on some of the older carter AFBs they had secondary air valve counterweights. With the hotter camshaft you might not be developing enough vacuum to "flop the doors open" at the times that you are trying. I would play with timing first...Paul
Mike
Well-Known Member
It can be pretty tough to get a recommendation on carb settings that will actually work in all instances. When you look at all the variables that come into play with something like tuning an accelerator pump circuit, about the only way to get ir right for you is to test, test, test.
For those of you with solid lifter camshafts, hook up a vacuum gauge and take an idle reading. Now bump the timing up 2 and take another reading. Now retard it 4 and read it again. Now change your valve lash by .002. See all those different numbers? That vacuum level is what the carb is depending on, just to work at all, and look how you've affected it.
I always get a kick out of guys that hammer and bang on carbs, whilst running a motor on a dyno. Heck, leave me in the dyno room alone for two minutes and I'll find you a lot of power and never touch the motor. If you're looking for magic numbers, that's easy to do. But a dyno is a static environment, whereas different cars have different weights, different gear ratios, different torque converters, etc. Toss in varying barometric pressures, temperatures, grains of water, etc. and it's a wonder we can ever get a carb to work in so many different conditions.
Your best bet is to buy one of the Edelbrock kits with the different metering jets, step-up rods and springs. Find an afternoon where you can spend some time playing and see what your car wants. Standardize your tests, so you're not trying to drive uphill on one test and downhill on the next. And do it all in one afternoon, not one day when it is 76 and the next evening when it is down to 48. Change one thing at a time, so you can always come back to where you were if it goes wrong. It won't take long before you make the motor happy.
For those of you with solid lifter camshafts, hook up a vacuum gauge and take an idle reading. Now bump the timing up 2 and take another reading. Now retard it 4 and read it again. Now change your valve lash by .002. See all those different numbers? That vacuum level is what the carb is depending on, just to work at all, and look how you've affected it.
I always get a kick out of guys that hammer and bang on carbs, whilst running a motor on a dyno. Heck, leave me in the dyno room alone for two minutes and I'll find you a lot of power and never touch the motor. If you're looking for magic numbers, that's easy to do. But a dyno is a static environment, whereas different cars have different weights, different gear ratios, different torque converters, etc. Toss in varying barometric pressures, temperatures, grains of water, etc. and it's a wonder we can ever get a carb to work in so many different conditions.
Your best bet is to buy one of the Edelbrock kits with the different metering jets, step-up rods and springs. Find an afternoon where you can spend some time playing and see what your car wants. Standardize your tests, so you're not trying to drive uphill on one test and downhill on the next. And do it all in one afternoon, not one day when it is 76 and the next evening when it is down to 48. Change one thing at a time, so you can always come back to where you were if it goes wrong. It won't take long before you make the motor happy.
Mike said:
Ok i got tired of listening to you guys argue about Holley SOO i bought a Edelbrock 600 for the 351w i should have it tomorrow or Thursday.I got it from Summit cause i have a $30.00 off coupon so it came to $255.95 plus $11.00 handling charge.Tell me why something that cost $98.99 has no handling charge and anything over $100.00 has one.I also have a Holley 600 4160 electric choke carb that needs a home.
Lee_in_KC
Active Member
In a blower book I have (Supercharging for the Street by Pat Ganahl), there is a section on tuning Carter/Edelbrock vacuum secondary carbs. The cure for early opening of the secondaries is to increase the counter-balance weights on the secondary butterflies. The book says there used to be kits available but not as of the writing of the book (last updated in 2002 IIRC). The book gives some general suggestions on how you could DIY heavier weights. One idea for a small adjustment was to dribble solder onto the weights (remove the butterflies from the carb first 
). Another was to cast new larger weights using plumber's lead.
I'll try to remember to bring the book to work tomorrow so I can scan the photos showing the weights.
). Another was to cast new larger weights using plumber's lead.I'll try to remember to bring the book to work tomorrow so I can scan the photos showing the weights.
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